Richmond, Va. - The OPTN/UNOS Board of Directors, meeting June 24 and 25, approved substantial amendments to OPTN policy for deceased donor kidney allocation. The policy will maintain access to kidney transplantation for all groups of candidates while seeking to improve outcomes for kidney transplant recipients, increase the years recipients may have a functioning transplant and increase utilization of available kidneys. The implementation date of the policy was not immediately established but is expected to occur in 2014. "These changes will result in better long-term kidney survival and more balanced waiting times for transplant candidates," said OPTN/UNOS President John Roberts, M.D.
Matching to increase benefit and utilization
More than 96,000 people are currently listed for kidney transplantation nationwide. About 10 percent of kidney candidates die each year while waiting. Because there are not enough kidneys donated to meet the need, it is important to improve benefit by matching recipients according to the potential function of the kidney and ensure as many kidneys as possible are transplanted.
The newly approved policy includes new factors not used in the current policy. Their use is recommended to enhance survival benefit and use of available kidneys.
Existing policy definitions of "standard criteria" and "extended criteria" donors will be replaced with the Kidney Donor Profile Index (KDPI), a clinical formula that classifies donor kidneys based upon how long they are likely to function once transplanted. Kidney transplant professionals already have access to this index as an informational resource.
The policy will also include a clinical formula to estimate the number of years each specific candidate on the waiting list would be likely to benefit from a kidney transplant. This score is called the Estimated Post-transplant Survival formula (EPTS).
Under the new policy, when a kidney donor is entered into the matching system, that individual donor's KDPI score will be considered along with the individual EPTS for compatible candidates. "A limited number of kidneys expected to function the very longest will be considered first for the candidates expected to need them for the longest amount of time," said John Friedewald, M.D., chairman of the OPTN/UNOS Kidney Transplantation Committee.
The policy is expected to increase overall "life-years" (time that recipients retain kidney function after the transplant). It may also reduce recipients' future need for repeat transplants, thus allowing more transplants among candidates awaiting their first opportunity.
The kidney matching process would not change for the majority of kidney transplant candidates unless they receive additional priority based on other considerations addressed below.
Promoting greater utilization
The 15 percent of kidney offers estimated to have the shortest potential length of function based on KDPI score will be offered on a wider geographic basis. Transplant programs may be most likely to consider these offers for candidates who would have a better life expectancy with a timely transplant than they would remaining on dialysis. This feature is expected to increase utilization of donated kidneys currently available for transplant. It may also help minimize differences in local transplant waiting times across different regions of the country.
The policy does not affect the decision-making process between an individual candidate and his or her transplant team regarding kidney offers they would be willing to accept for a transplant. The use of KDPI will provide the candidate and transplant team a clearer understanding of the potential function of the kidney to allow for more informed treatment decisions.
Waiting time calculation
As in the current kidney allocation system, the longer a candidate has waited for a transplant, the more priority he or she will have compared to others who have waited less time.
The current national default policy assigns waiting time when the candidate is listed with a program, even if he or she had begun dialysis or met other criteria for end-stage kidney failure before being listed.
Under the amended policy, once a person is accepted as a transplant candidate, waiting time will be calculated from the date the person first had a GFR score (a standard clinical measure of kidney function) less than or equal to 20 ml/minute, or when the candidate began dialysis or other renal replacement therapy, even if that date preceded the transplant listing.
Access for candidates with biological disadvantages
The revised policy will enhance access to transplantation for candidates with biological disadvantages including less common blood types and/or high immune system sensitivity.
The policy will facilitate kidney offers from donors with certain subtypes of blood type A for transplant candidates with blood type B. Some type B candidates are compatible with donors who have these specific subtypes.
The policy also creates a sliding scale of additional priority for candidates with an immune system sensitivity, measured in a percentage using a calculated panel reactive antibody (CPRA) score, beginning at 20 percent. Since extremely highly sensitized candidates (CPRA score of 98 percent or higher) have very few opportunities for a compatible transplant, they would receive higher proportional priority than those with more moderate sensitization levels.
Upon implementation of the policy, local organ allocation areas will no longer owe "payback" kidney debts when a transplant center accepts a well-matched kidney offer from a different local donation service area. Research has not shown any definable benefit in recipient outcomes from payback offers.
A number of alternate kidney allocation systems currently operated in different local areas of the country will also end upon policy implementation. Many of these local systems were intended to study allocation methods now incorporated into the national policy proposal.